A Monitoring Approach Based on Fuzzy Stochastic P-Timed Petri Nets of a Railway Transport Network
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Hindawi Journal of Advanced Transportation Volume 2021, Article ID 5595065, 18 pages https://doi.org/10.1155/2021/5595065 Research Article A Monitoring Approach Based on Fuzzy Stochastic P-Timed Petri Nets of a Railway Transport Network Anis M’hala Laboratory of Automation, Electrical Systems Environment (LAESE), National Engineering School of Monastir (ENIM), Monastir, Tunisia Correspondence should be addressed to Anis M’hala; [email protected] Received 8 January 2021; Revised 1 April 2021; Accepted 5 April 2021; Published 27 April 2021 Academic Editor: Socrates Basbas Copyright © 2021 Anis M’hala. *is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. *is paper proposes a monitoring approach based on stochastic fuzzy Petri nets (SFPNs) for railway transport networks. In railway transport, the time factor is a critical parameter as it includes constraints to avoid overlaps, delays, and collisions between trains. *e temporal uncertainties and constraints that may arise on the railway network may degrade the planned schedules and consequently affect the availability of the transportation system. *is leads to many problems in the decision and optimization of the railway transport systems. In this context, we propose a new fuzzy stochastic Petri nets for monitoring (SFPNM). *e main goal of the proposed supervision approach is to allow an early detection of traffic disturbance to avoid catastrophic scenarios and preserve stability and security of the studied railway networks. Finally, to demonstrate the effectiveness and accuracy of the approach, an application to the case study of the Tunisian railway network is outlined. 1. Introduction derailment, which happened near Sahline, 10 km south of Sousse, is especially relevant (numerous injured passengers). Railway industry plays a critical role in transportation and transit *e inquiry commission determined that the accident resulted systems attributed to the ever-growing demand for catering to from failure of the railroad switch, holding the maintenance both freight and passengers. However, owing to many challenges company responsible for the failure. In this context, it is es- faced by railway stations such as harsh environments, traffic sential to develop a supervision approach allowing to avoid flow, safety, and security risks, new and adaptive systems catastrophic scenarios and to further rail safety. employing new technology are recommended [1]. Our study is devoted to the modeling and monitoring of In the railway transport system, the processing times are the Tunisia railway transport networks by using stochastic interval-valued with parameters that depend on the oper- P-timed Petri nets in order to control traffic and to avoid ation to be performed. Any deviations from the specified disruptions problems. *e approach proposed in this paper interval will characterize a traffic disturbance. Consequently, is based on a statistical analysis of the real measurements, the monitoring of the time intervals will be used as the main collected by the Supervisory Control and Data Acquisition principle to detect and isolate the disturbances that affect the (SCADA) system of the Tunisian National Railway Company system. *e system that motivated this study is a real railway (TNRC), to identify the time parameters of the stochastic transport network in Tunisia. P-timed Petri net (SP-TPN) model. In particular, the ap- To reduce road congestion in urban areas, railway proach determines the dynamic time intervals associated networks are coming under increasing strain. In Tunisia, with the places of the SP-TPN and the resulting probability integrity rail services are operated in many metropolitan density functions (PDF) of the travelling and parking times. areas but most notably in the Tunisian Sahel region. *e main objectives are to analyze the traffic conditions by Safety is of critical concern, particularly given the recent simulation and to monitor the traffic by avoiding possible high-profile rail accidents featured in the media. *e metro troubles and perturbations. 2 Journal of Advanced Transportation Our study concerns the Tunisian railway transport including advanced WSNs, which will enhance security, system, particularly, in the Tunisian Sahel region. *is safety, and decision-making processes to achieve more cost- system must respond to different requirements, minimizing effective management in railway stations, as well as the the waiting times in the stations, respecting schedules, and development of integrated systems. *e authors demon- ensuring the safety of passengers and equipment. In our strate that the size, efficiency, and cost of WSNs are influ- previous works [2], synchronized Petri nets (P-TPNs) are ential factors that attract the railway industry to adopt these used to model railway transport systems. In this way, the devices. modeling process is greatly simplified, and the complexity of Kulbovskyi et al. [11] propose a new monitoring ap- the model is widely reduced. In [2], an identification of the proach for a power supply network system. *e proposed P-TPN model of the Sahel railway network in Tunisia was monitoring model shows information chains between sys- made. *e objective was to identify the temporal parameters tem components and their object, generalized structure of of the model from a set of real measurements collected by the original data flow-over, particulrly, controlling decisions SCADA system of TNRC. and external effects within the information and computer *e contributions of the present paper are as follows: system. In order to identify emergency and abnormal op- erating regimes of electrical networks in real-time mode, an (i) *e improvement of the time semantic of the railway application to railway power supply network was proposed. network model with the introduction of the sto- *e development of algorithms for detecting failures in chastic P-timed Petri nets (SP-TPNs) railway catenary support components was proposed by Liu (ii) A new supervision approach, based on the study of et al. [12]. In this context, virtual reality technology is effective sojourn time of the token in places and the employed to control the learning environment of con- evaluation of the probability density functions (PDF) volutional neural networks (CNNs) for the automatic of the travelling times, is proposed. *is approach is multicamera-based monitoring of catenary support com- used to evaluate the influence of different types of ponents. First, 3D image data based on drawings and real- disturbances on the expected schedule. life video images are developed. *en, a virtual reality en- *is paper is organized as follows. Section 2 presents the vironment for monitoring the railway catenary support state of the art. Section 3 presents the studied railway system is created, emulating real-life conditions such as transport system and the SP-TPN model of the railway measurement noise and a multicamera train simulation to network of the Sahel Tunisia. Afterward, the problem of resemble state-of-the-art monitoring systems. monitoring of railway transport networks is tackled. An On the other hand, Mishra [13] proposed an anticolli- original supervision approach based recovery approach sion system named “TMCAS” (train monitoring and col- based on stochastic P-timed Petri nets is presented. lision avoidance system) that uses a protocol to share and In Section 5, an application of the developed monitoring exchange position, speed, and the signal at danger infor- approach to realistic railway is proposed. Finally, a con- mation between trains and central control room. TMCAS clusion is presented with some perspectives. aims to automate train operations and act as a safety en- hancement system by ensuring speed control, rear-end and 2. State of the Art head-on collision avoidance, and signal-at-danger avoidance. Railway transport systems must be monitored online to Some other works are interested in the online moni- avoid situations that may be critical because of disturbances. toring of railway traffic in presence of unpredictable events. *ese disturbances can affect the railway infrastructure or Pinto et al. [14] presents a contactless system to measure traffic management, and that they can lead to a degradation track displacements and its application in an embankment/ of the transport service. *e general objective is to maintain underpass transition zone, located on the Northern line of the stability of the railway network and make it more effi- the Portuguese railway network where the Alfa Pendular cient and secure. In this context, various research projects tilting train travels at a maximum speed of 220 km/h. *e were conducted on the monitoring of transportation systems system is based on a diode laser module and a position to save time and improve the quality of rail service [3–9]. sensitive detector (PSD). *e PSD receives the laser beam Among many related research studies, Bennet et al. [10] emission, and the detection of the center of gravity of the propose an identification of the critical factors that should be beam spotlight on the PSD area enables the calculation of the considered in the design of a wireless sensor network, in- displacement. *e optical measuring system proved to be an cluding the availability of electrical power and communi- efficient and flexible way to measure absolute and relative cations networks in railway transport. Various issues facing